Field of the Invention
The present invention relates to a technique of correcting the blur of a captured image by using a plurality of correction optical systems.
Description of the Related Art
Recently, an image blur correction function, which not only corrects the blur of a captured image caused by camera shake while the user is standing still but also corrects a relatively large blur caused when the user performs shooting with one hand and the large blur of a captured image caused when the user performs shooting while walking, has become widespread.
Image blur correction methods include techniques such as an optical image blur correction technique of shifting an optical axis in accordance with blur by optically moving a correction lens and an electronic image blur correction technique of changing a cutout region output from an image captured by an image sensor in accordance with blur.
In order to correct a large blur, an optical image blur correction scheme needs to increase a correction angle, whereas an electronic image blur correction scheme needs to set a large surplus pixel region. Either method needs to expand a correction range. When expanding a correction range, however, the optical image blur correction scheme suffers from a problem that a lens or an actuator increases in size or the optical performance deteriorates when the lens is greatly shaken. In addition, the electronic image blur correction scheme suffers from a problem that a reduction in an effective region leads to a deterioration in image quality and an increase in the size of an image sensor leads to an increase in power consumption.
In order to solve such problems, Japanese Patent Laid-Open No. 2003-202499 has proposed a method of providing and driving two correction optical systems for shake correction. In addition, Japanese Patent Laid-Open No. 2010-4370 has proposed a method which provides a correction optical system and an electronic correction system and corrects blur by separating it into a high frequency band and a low frequency band and performing correction for each frequency band using two correction systems.
The conventional techniques disclosed in Japanese Patent Laid-Open Nos. 2003-202499 and 2010-4370, however, give no consideration to control at the time of a zoom operation. For this reason, the following problem arises.
That is, when separating the frequency band of the shake and performing correction using the two correction optical systems, the movable ranges of the two correction optical systems change by an optical characteristic according to a focal length. For this reason, it is necessary to switch between the system in charge of correcting a high-frequency component and the system in charge of correcting a low-frequency component in accordance with the focal length in order to ensure a desired shake correction performance. However, if the switching between the system in charge of correcting the high-frequency component and the system in charge of correcting a low-frequency component is done during the zoom operation, a failure in image blur correction such as an end hit occurs along with a change in the movable ranges.